medusa used to think to call menstruation the "curse" is a derogatory patriarchal coinage. she still think so, but she also thinks that the truth value of that coinage is too potent to be ignored. why else will someone be subjected to a week's angst because it is late, and live in perpetual horror of the bad things that might be happening inside her.
and then when the blessed (surely you mean cursed?) moment comes, it brings with it headaches and back aches, stomach aches that do not go away with pain killers, acute depression (wait a min, chums are supposed to cure you of your pre menstrual stress, so what depresseion now?), nausea and what not. reducing a perfectly functioning human being to a mess (literally and figuratively...eeeew, dont be gross) the curse stays on for a week, and goes away only when you are bordering on anaemia.
if you still want to know the reason behind this post dear reader, take another guess.